Biomedical subjects

Y Noguchi

Publications and source records attributed to Y Noguchi.

At least 163 records · Page 9Linked to original sources

PubMed1997

Detection of lipid peroxidation and hydroxyl radicals in brain contusion of rats.

To examine the relationship between the free radicals and brain tissue damage, we investigated the intensity of brain hydroxyl (OH) radical generation and lipid peroxidation in the rat contusion injury model. A unilateral contusion was induced by a weight-drop method. All rats were decapitated six hours after the injury, and brain samples were taken from three portions (core, peripheral, and distal) to examine the specific gravity as an indicator of brain edema, generation of OH using an electron paramagnetic resonance spectrometer (EPR), and malondialdehyde (MDA) and 4-hydroxyalkenals production. Analysis of the specific gravity revealed cerebral edema on the ipsilateral side in the injured group. The signal intensity of EPR in the core and peripheral portions in the contusion group was significantly higher than that in the distal portion of the contusion group and that of all portions in the control animals. No significant difference was observed between the core and peripheral portions of the contusion group. The MDA and 4-hydroxyalkenals production was significantly higher in the core and peripheral portions than in the distal portion of the contusion group and that of all portions of the control group. The degree of posttraumatic brain edema was closely correlated with the increase of DMPO-OH adduct, MDA, and 4-hydroxyalkenals. These results support the current concept that free radical production following traumatic brain injury may induce lipid peroxidation and may be the direct cause of edema formation.

Animals↗

PubMed1997

Effects of lecithinized SOD on contusion injury in rats.

To analyze the effect of lecithinized superoxide dismutase (SOD) on superoxide accumulation after traumatic injury, the expression of Cu,Zn-SOD mRNA was examined after contusion in rat using Northern blotting. As determined by specific gravity, lecithinized SOD decreased brain edema. The expression of Cu,Zn-SOD mRNA increased at the core, peripheral and contralateral hemisphere of injury. These increases were then suppressed by lecithinized SOD. Our results support the hypothesis that superoxide may play an important role in edema formation after contusion, and that lecithinized SOD appears to prevent brain edema through a protective effect against superoxide injury.

Animals↗

PubMed1997

Cochlear microphonics recordable at the non-shielded bedside using a new tubal transducer.

A new tubal transducer (NC-3) for measuring cochlear microphonics (CM) in extratympanic electrocochleography (ECochG) was developed by improving the common hearing aid earphone. Using a human forearm as a dummy ear, the artifact contamination generated from the NC-3 tubal transducer was tested and the possibility of measuring the CM at a non-shielded bedside was studied. An HN-5 electrode was fixed to a subject's forearm, and a sound stimulus of 90 dBnHL was delivered through the tube of the NC-3. When the earphone of the transducer was placed at a right-angle to the electrode on either a vertical or horizontal plane and the electrode was placed in direct contact with the tip of the tube, contamination from electromagnetic induction and CM-like mechanical vibration were prevented. Using the HN-5 electrode and NC-3, extratympanic ECochG-CM was recorded from normal-hearing subjects in both a shielded soundproof room and a non-shielded ordinary, quiet room. No differences were found between CMs measured in the two rooms. These results suggest that the NC-3 overcomes the shortcomings of a loudspeaker system and allows CM to be recorded accurately at non-shielded bedsides.

Acoustic Stimulation↗

PubMed1997

Increased glutamine consumption in small intestine epithelial cells during sepsis in rats.

BACKGROUND: Previous reports have emphasized increased intestinal glutamine consumption during sepsis. This may be of clinical significance as glutamine is a (and perhaps the) physiologic fuel for the intestine. A problem remains, however, as glutaminase, the major enzyme for the degradation of glutamine, is decreased rather than increased in sepsis. This implies an alteration in the metabolic fate of glutamine in sepsis, which may be of clinical significance. METHODS: We determined the effect of sepsis on glutamine metabolism in mucosa of small intestine. Sepsis was induced in rats by cecal ligation and puncture. Control rats were sham-operated. After 16 hours, glutamine consumption was measured in isolated enterocytes, and glutaminase, glutamine synthetase, and glutamine transaminase activities and DNA synthesis were determined in mucosa. RESULTS: Glutamine consumption was increased during sepsis in enterocytes from the tips of the villi and was unchanged in enterocytes from the midportions of the villi and the crypts. As previously shown, mucosal glutaminase activity was reduced. However, glutamine synthetase and glutamine transaminase activities were stimulated in septic rats, suggesting an increase in metabolism of glutamine via alternate pathways. DNA synthesis was increased during sepsis, especially in crypt cells. CONCLUSIONS: Increased or unchanged glutamine consumption in enterocytes from septic rats, despite reduced glutaminase activity, appears to reflect increased activity of other enzyme systems and/or increased utilization of the amino acid for DNA and protein synthesis. Since other aspects of glutamine metabolism may also be deranged in sepsis, a continual enteral supply of glutamine to the intestinal lumen during sepsis may be clinically useful.

Animals↗

PubMed1997

Surgical strategy for doubly committed subarterial ventricular septal defect with aortic cusp prolapse.

BACKGROUND: Many surgeons recommend early repair of doubly committed subarterial ventricular septal defect regardless of the clinical symptoms. We reviewed our patients of this anomaly with aortic cusp prolapse to justify this strategy. METHODS: We reviewed the preoperative and postoperative records of 27 patients with doubly committed subarterial ventricular septal defect and aortic cusp prolapse. The patients' ages ranged from 2 months to 11 years (median, 4.6 years). RESULTS: During the preoperative observation period, aortic regurgitation (AR) developed in 65% of the patients. In the 8 patients without AR before the operation, AR did not develop after the operation, whereas AR persisted in 12 (63%) of the 19 patients with preoperative AR. To identify the risk factors for persistent AR after the operation we analyzed the data for the patients with preoperative AR in the persistent AR group (n = 12) and eliminated AR group (n = 7) and found a longer period from the onset of AR to the operation in the persistent AR group (32.1 +/- 10.1 versus 5.6 +/- 1.9 months; p = 0.014). During the follow-up period 10 of the 17 patients with mild AR before the operation showed persistent AR in the postoperative period, but it did not progress. CONCLUSIONS: We conclude that early surgical repair with a minimum observation period is essential for prevention of residual AR. Even if a tiny AR is detected preoperatively, the patient should be surgically treated immediately.

Age Factors↗

PubMed1997

Vestibular schwannoma showing a dural tail on contrast-enhanced magnetic resonance images.

The dural tail on contrast-enhanced magnetic resonance (MR) images, frequently observed in meningiomas, has been used to distinguish between cerebellopontine angle meningiomas and vestibular schwannomas. We report on a 66-year-old female with vestibular schwannoma showing the dural tail on contrast-enhanced MR images. Histological examination revealed that the dural tail corresponded to the thickened dura mater comprising of collagen fibres and scattered hyalinization with no tumoral invasion.

Aged↗

PubMed1997

Beta-galactosidase-deficient mouse as an animal model for GM1-gangliosidosis.

GM1-gangliosidosis is a progressive neurological disease in humans caused by deficiency of lysosomal acid beta-galactosidase, which hydrolyses the terminal beta-galactosidic residue from ganglioside GM1 and other glycoconjugates. In this study, we generated a mouse model for GM1-gangliosidosis by gene targeting in embryonic stem cells. The mouse homozygous for the disrupted beta-galactosidase gene showed beta-galactosidase deficiency, presented with progressive spastic diplegia, and died of emaciation at 7-10 months of age. Pathologically, PAS-positive intracytoplasmic storage was observed in neuronal cells of various areas in the brain. Biochemical analysis revealed a marked accumulation of ganglioside GM1 and asialo GM1 in brain tissue. This animal model will be useful for pathogenetic analysis and therapeutic trial of human GM1-gangliosidosis.

Animals↗

PubMed1997

Contamination of microbial foreign bodies in bottled mineral water in Tokyo, Japan.

A total of 292 imported and domestic bottled mineral waters (90 brands) obtained from consumers and retailers were examined, by eye, for observable microbial foreign bodies. Fungal and bacterial foreign contaminants were found in 45 samples of water (20 brands) and in 14 samples of water (10 brands), respectively. Of the samples of water found to be contaminated, 41 (22 brands) were imported and 18 (8 brands) were produced domestically. Of 22 brands that were contaminated, 20 (91%) had been sterilized by at least one method. Forty-eight (98%) of 49 samples confirmed with foreign bodies were less than 1 year old. Among the moulds isolated the most predominant genus was Penicillium, followed by Acremonium and Cladosporium. The samples that contained fungi were less contaminated by bacteria than those that contained observable bacterial foreign bodies.

Bacteria↗

PubMed1997

Effects of lecithinized superoxide dismutase on traumatic brain injury in rats.

Only small amounts of superoxide dismutase (SOD) are present in the extracellular space to scavenge excess amounts of superoxide anions (02-) released after traumatic brain injury (TBI). Experiments were performed in rats with cerebral contusion produced by weight-drop technique. We investigated the effects of exogenous lecithinized SOD (PC-SOD) on accumulation of 02- produced in our model, by measuring the level of SOD activity (using the NBT-reducing method) and the expression of copper, zinc-SOD (Cu, Zn-SOD) mRNA (by Northern blot analysis). As determined by tissue-specific gravity, administration of PC-SOD reduced brain edema in the periphery of the lesion 6 h after contusion. SOD activity increased in the peripheral region at 30 min after contusion, but returned to normal levels at 6 h after TBI. Administration of PC-SOD increased SOD activity up to 6 h after TBI. The expression of Cu, Zn-SOD mRNA increased in the core region, peripheral portion, and contralateral hemisphere up to 6 h after TBI, then was suppressed in all three regions by PC-SOD. Our results confirm the important role of 02- in the development of brain edema after TBI and indicate that PC-SOD diminishes brain edema through a protective effect against 02-.

Animals↗

PubMed1997

Characteristics of toxicity and haemorrhagic toxin produced by Clostridium sporogenes in various animals and cultured cells.

The toxic effects of the haemorrhagic toxin of Clostridium sporogenes were studied in mice, rats, guinea-pigs and rabbits, and in various cultured cells. In rabbits, but not in the other animals, intradermal injection with crude toxin and its injection into a ligated intestinal loop caused haemorrhage in both the skin and intestinal wall. Intraperitoneal (i.p.) injection of crude toxin similarly caused death only of rabbits, with marked haemorrhage in the serous surface of kidney, intestines, liver, spleen, mesentery and diaphragm. Histological examination of the rabbits killed after i.p. inoculation revealed leakage of blood into a space beneath the serous membranes of parenchymatous organs in the peritoneal cavity and within the loose connective tissues in the mesentery and diaphragm. Cytotoxicity of partially purified haemorrhagic toxin in vitro was noted with rabbit aorta endothelial cells, human skin capillary vein endothelial cells and bovine pulmonary artery endothelial cells, but not with Chinese hamster ovary cells, Vero cells, human epitheloid carcinoma cells, human colon carcinoma cells (T84) and human colon adenocarcinoma cells (Caco 2). The results suggest that the haemorrhagic toxin of C. sporogenes exerts its effects in rabbits but not in mice, rats or guinea-pigs, through direct action on endothelial cells.

Animals↗

PubMed1997

Magnetic resonance imaging of the cauda equina in two patients with Guillain-Barré syndrome.

The results are presented of magnetic resonance imaging (MRI) of the spine in two cases of childhood Guillain-Barré syndrome. After injection of gadolinium-diethylenetriamine pentaacetic acid, MRI showed enhancement of the cauda equina in these patients. These MRI observations may help confirm the diagnosis of Guillain-Barré syndrome. The nerve root enhancement resolved as the clinical symptoms improved. Serial imaging may be useful in monitoring the response to therapy and assessing new treatment regimens. It may also yield a better understanding of the disease process.

Cauda Equina↗

PubMed1997

[Sporadic diarrhea caused by Vibrio cholerae non-O1 and characteristics of the isolates].

In 1996, we examined five domestic and eight imported cases of sporadic diarrhea caused by Vibrio cholerae non-O1 in Tokyo. The domestic cases occurred during the summer, from June to September, while the imported cases were seen throughout the year. The major clinical symptoms of the patients were watery diarrhea (100%) with an average frequency of 5.5 times/day, abdominal pain (77%), vomiting (31%) and fever (15%). A total of 13 strains isolated from these 13 cases had the typical biochemical characteristics of Vibrio cholerae, and were classified into 11 kinds of serovars (O2, O5, O8, O9, O12, O14, O27, O51, O88, O97, and O161). All strains produced hemolysin, and two strains produced NAG-ST, while no strain produced cholera toxin.

Adult↗

PubMed1997

[Shigella dysenteriae strains possessing a new serovar isolated from imported diarrheal cases in Japan].

Two Shigella strains (93-119 and 95-619) isolated from stool cultures of imported diarrheal cases in Japan, did not react to any antisera of the established SHigella serovars. These strains had the typical biochemical characteristics of Shigella dysenteriae, and were biochemically identical to each other. Both strains were positive in the Serény test and other tests for invasiveness; these indicate that they can cause shigellosis in humans. The results of antigenic analysis showed that they did not belong to any of the recognized or provisional serovars, and were serologically indistinguishable. Strain 93-119 is designated as the test strain for this new serovar.

Animals↗

PubMed1997

[Simple method for typing human immunodeficiency virus type I (B, E) by PCR and chronological change of distribution of subtype (B to E) in Japan].

We analyzed the clade distribution of B and E in HIV-1 isolates in Japan by a nested PCR method using 5'-CCCACAAGATTTAAATATG-3' of the gag gene as clade B primer and 5'-CCCACAAGATTTAAACTCC-3' of the gag gene as clade E primer. Seventy-two anti-HIV-1 confirmatory positive serum samples were collected during a period of 1991-1996 in two hospitals in Yokohama City. Peripheral blood mononuclear cells were obtained from the buffy coat of these samples and extracted DNA were used for nested PCR. The 72 cases comprised of 11 Japanese hemophiliacs, 14 Japanese male homosexuals, 19 Japanese male heterosexuals, 5 Japanese female heterosexuals and 23 Thai female heterosexuals. Of these 36 were clade B and 35 were clade E and one case showed positive PCR results for both B and E primers. Almost all male Japanese hemophiliacs and homosexuals in our sample have clade B, while the female Thai heterosexuals have clade E, irrespective of the year of isolation. As for Japanese male heterosexuals, through 1993, clade B was predominant but since 1994, the predominate clade switched to clade E. Although the number of Japanese female heterosexuals in our sample is small, clade B was isolated in 2 cases even after 1994.

Female↗

PubMed1997

Cloning of genes coding for L-sorbose and L-sorbosone dehydrogenases from Gluconobacter oxydans and microbial production of 2-keto-L-gulonate, a precursor of L-ascorbic acid, in a recombinant G. oxydans strain.

We have purified L-sorbose dehydrogenase (SDH) and L-sorbosone dehydrogenase (SNDH) from Gluconobacter oxydans T-100 that showed an ability to convert D-sorbitol to 2-keto-L-gulonate (2-KLGA). A genomic library of Gluconobacter oxydans T-100 was screened with a probe, a 180-bp PCR product which was obtained from degenerate oligodeoxyribonucleotides based on the elucidated sequence of the purified SDH (used as primers) and the genomic DNA of G. oxydans T-100 (used as a template). From sequencing of the DNA from a clone positive to the probe, the SNDH and the SDH were estimated to be coded in sequential open reading frames with 1,497 and 1,599 nucleotides, respectively, which was confirmed by expression of the DNA in Escherichia coli that showed both enzymatic activities. The DNA was introduced to a shuttle vector which was prepared from a plasmid of G. oxydans T-100 and pHSG298 to obtain an expression vector designated pSDH155. The production of 2-KLGA by pSDH155 in G. oxydans G624, an L-sorbose-accumulating strain, was improved to 230% compared to that of G. oxydans T-100. Chemical mutation of the host strain to suppress the L-idonate pathway and replacement of the original promoter with that of E. coli tufB resulted in improving the production of 2-KLGA. Consequently, high-level production from D-sorbitol to 2-KLGA (130 mg/ml) was achieved by simple fermentation of the recombinant Gluconobacter.

Acetobacteraceae↗

PubMed1997

Influence of hypoxia on endothelin-1 binding sites in neonatal porcine pulmonary vasculature.

Exposure to chronic hypobaric hypoxia in the newborn piglet causes pulmonary hypertension and structural abnormalities in the intrapulmonary arteries that resemble those seen in babies with pulmonary hypertension of the newborn. To investigate whether the density and subtype of endothelin (ET) receptors in intrapulmonary arteries were altered by exposure to chronic hypobaric hypoxia (50.8 kPa) and changed on recovery, (125)I-labeled ET-1 binding was studied using an in vitro autoradiographic technique on 67 piglets. Plasma ET was measured in 116 control, hypoxic, and recovery animals. In piglets exposed to hypoxia from birth, plasma ET was greater than normal for age (P < 0.05), and the binding density of ET-1 was increased in elastic arteries, muscular arteries, and veins due to an increase in the density of ET(A) binding (P < 0.05 for all vessel types). On recovery, plasma ET level became normal after 6 days. After 1 day of recovery, the binding density of ET-1 and ET(A) was normal in elastic arteries but was greater than normal in muscular arteries even after 6 days (P < 0.05). Exposure to hypoxia from 3 to 6 or from 14 to 17 days did not alter the plasma ET or the binding density in muscular arteries, but the density of binding of ET-1, ET(A), and ET(B) in elastic pulmonary arteries decreased (P < 0.05). On recovery, it returned to normal by 6 days. In summary, the increases in plasma ET and ET-1 and ET(A) binding density suggest a role for ET in the pathogenesis of hypoxic pulmonary hypertension in the newborn period. An initial normal period of adaptation is protective.

Aging↗

PubMed1997

Bronchial artery aneurysm as a cause of atelectasis.

A 54-year-old nonsmoker female developed atelectasis of the anterior basal segment of the right lower lobe. A non-pulsating endobronchial tumor was observed bronchoscopically obstructing the right basal bronchus. The tumor was confirmed on arteriography to be a saccular aneurysm of the right bronchial artery. The aneurysm was treated with bronchial artery embolization. Bronchial artery aneurysm, without a predisposing disease, is quite rare, but should be considered as an etiological factor of atelectasis.

Aneurysm↗

PubMed1997

[Clinical study in vertiginuous patients suspected of having neurovascular compression syndrome of the eighth cranial nerve].

Neurovascular compression syndrome of the 5th and 7th cranial nerves has been recognized as the cause of trigeminal neuralgia and hemifacial spasm. On the other hand, it is still difficult to diagnose vertigo as neurovascular compression syndrome of the 8th cranial nerve. To detect some specific finding in this syndrome of the 8th cranial nerve, 5 patients with vertigo with hemifacial spasm were examined for the clinical course and neuro-otological features. In all patients MRI and/or angiography suggested vascular compression against the 8th cranial nerve. The clinical courses of these patients revealed various symptoms resembling benign paroxysmal positional vertigo, vestibular neuronitis and Meniere's disease. Audiograms showed two normal hearing patterns, bilateral high frequency hearing loss probably due to aging in one case, bilateral C5-dip in one and fluctuating unilateral hearing loss like Meniere's disease in one. The prolongation of IPL I-III on auditory brainstem response proposed as a criterion by Møller was detected in one case. No response in the caloric test was found in two cases. These abnormalities in the auditory brainstem response and caloric test appeared to be useful for diagnosis but were uncommon findings in all cases. Electronystagmographic examinations including the eye tracking test, optokinetic nystagmus and optokinetic pattern were all normal. We could not find any specific clinical findings valuable for diagnosis of neurovascular compression syndrome of the 8th cranial nerve. It is proposed that the indication of microvascular decompression should be decided carefully.

Cerebral Angiography↗